What is of, pertaining to, or designating, an acid known only in its salts (the metatungstates) and properly called polytungstic, or pyrotungstic, acid called?

metatungstic — Of, pertaining to, or designating, an acid known only in its salts (the metatungstates) and properly called polytungstic, or pyrotungstic, acid. (Webster's 1913.)

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